Exploring Design Trades to Extend Useful Life of Platform Terminal Transmitters on Sea Turtles

Abstract

Abstract Satellite-linked platform terminal transmitters (PTTs) are important tools for conducting research of sea turtles in their marine habitats. Appropriate conservation actions can be identified using PTTs, mounted to the top of sea turtles’ shells, to collect information about migratory routes and habitat usage. However, there is concern that PTTs introduce hydrodynamic drag that may bias natural sea turtle behavior, making the migratory and habitat data inaccurate representations of the “untagged” population. PTTs also have limited attachment durations, hypothesized to be caused by hydrodynamic loading and shell expansion during growth. The aim of this research is to investigate the hydrodynamic drag induced by PTTs on juvenile hard-shelled sea turtles, with the broader goal of increasing deployment duration and minimizing behavioral effects. A computational fluid dynamics (CFD) model was created to simulate the hydrodynamics of juvenile sea turtles. The drag and lift coefficients for five PTTs, virtually attached to the sea turtle model, were calculated using numerical methods. A comparison table of PTT performance is presented. The results will be used to explore PTT form factor design trades-offs that reduce hydrodynamic loading, while still meeting operational requirements. This research could enable biologists to collect data that more accurately represents the untagged sea turtle population.